Network interface user devices, such as, for example, cable modems, are one way that multiple services operators (“MSO”) have been meeting the demand for increased bandwidth capabilities in delivering information over networks from a central location, such as a head end, to users, such as residential and commercial end-users. To facilitate such information delivery, standards have been developed that allow equipment from different manufacturers to operate, or ‘talk,’ with one another. The predominant standard used in the cable modem industry is known as Data Over Cable Service Interface Specification, or (“DOCSIS”), for use in delivering digital data, such as internet information, to users over the existing coaxial lines of the Community Antenna Television system (“CATV”), which has been delivering cable television programming to users at least since the 1960's.
As the DOCSIS standard evolves, more features are added that increase reliability, user-friendliness and performance. Thus, the growth of DOCSIS devices for obtaining broadband service has grown as well. Societies in which use of broadband services is growing rapidly tend to be mobile, i.e., people relocated often. People in these societies who subscribe to broadband services often own their equipment for interfacing with broadband networks, and therefore often prefer to take their broadband interface devices, such as cable modems, for example, with them when they relocate their residence of business location. Another common scenario occurs when a broadband customer who has a rented/leased user device/modem cancels service and the MSO redeploys the same device to another location when installing broadband service for another customer at another location.
When a subscriber or MSO relocates a user device, different central network equipment, such as, for example, a cable modem termination system (“CMTS”), may serve the new location than served the previous location—even if the MSO is the same. Alternatively, the same CMTS may serve two different locations using the same downstream channel frequency, but still not provide upstream connectivity over the same upstream channels that were provisioned for the old location. In summary, although downstream traffic at the downstream CMTS frequency used by the previous CMTS may be present at the second location of the user device, there may not be an upstream connection between the new location and the CMTS/blade that serves the new location.
Thus, when a user connects a device at the new location, the device may recognize the previous location's downstream frequency, based on an identifier associated therewith which may be stored in its memory cache, and tune (also referred to as lock) to said frequency. This can occur under the common scenario where a CMTS downstream channel signal can be received at different locations on the network. However, although a downstream signal may be received at multiple network locations, upstream channels provisioned and associated with a given downstream channel frequency may not always be physically connected from all locations on the network to the CMTS producing the given downstream channel.
Therefore, since there may be no upstream connection between the new location and the previous CMTS that are linked with the tuned-to frequency, the registration process does not complete because upstream communication transmission between the modem at the new location and the previous CMTS cannot be established. Since registration is not completed, the user device continues to scan for downstream frequencies that can be locked and that correspond to a CMTS that can receive the user device's upstream transmissions.
As this scanning process progresses, the user device typically periodically attempts to lock with frequencies stored in its cache memory if scanning for present downstream frequencies does not result in a lock. However, since the frequency identifier for the frequency used at the old location is still stored in the cache, the user device may repeatedly attempt to lock and establish communication with the CMTS generating the tuned-to frequency.
Therefore, time is wasted as the user device attempts to complete registration with the CMTS to which it cannot connect. Each time the user devices locks to a downstream frequency, it seeks to establish communication with the CMTS providing that downstream channel. However, if the locked-to downstream channel does not correspond to a CMTS with which the user device can communicate, then the time spent attempting to establish communication with the CMTS producing the downstream frequency to which the user device is locked it fruitless, and therefore wasted.
Thus, there is a need in the art for a method for eliminating the wasted time associated with repeatedly locking a user device to a downstream channel frequency not corresponding to a CMTS with which the user device can establish communication.